How do I install Pillow and/or Pip in Blender Python in Windows OS
Okay, I got it to work and in the off chance it might help a fellow (old) person, here's exactly what I had to do.

In the Windows PowerShell I first installed Pip by typing this command in the Python executable directory for Blender: 

.\python -m ensurepip --default-pip


Then I downloaded the Pillow wheel file for the version of Python I had (which I found by typing in .\python --version).  I put this file in the same directory as the Python executable (I don't know if I had to do this, but I did anyway).  Then I typed, again, specifically:

.\python -m pip install Pillow


Finally, inside of Blender itself my script did this:

From PIL import image


This worked -- and so I assume now I can use the stuff in the Pillow module (haven't tried that yet, but now I'm a LOT further along and I didn't have to uninstall my Blender Python).